JP2001082195A - Valve timing control device for engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent errorneous learning caused by a change of an external load to an engine when learning a reference position of a variable valve timing mechanism. SOLUTION: In this control device, in the case that an input signal of an air-conditioning switch is inverted, a most lag angle learning cancellation flag FLRCCL is set (S101, S102) to command cancellation of most lag angle learning. In the case that switching between a non-running range and a running range is executed, the most lag angle learning cancellation flag FLRCCL is set (S103, S102) to command the cancellation of the learning. When a lapsed time after the stop of the learning reaches a set time (S101-S105), the most lag angle learning cancellation flag FLRCCL is cleared (S107) to permit the most lag angle learning. That is, in the case that an external load changes, the learning is temporarily cancelled to prevent the errorneous learning caused by a change of actual valve timing calculated from both a crank angle and a cam position, and to prevent degradation of controllability in valve timing control from occurring.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a valve timing control apparatus for an engine having a variable valve timing mechanism for changing at least one of an intake valve and an exhaust valve of the engine in accordance with an operating state of the engine. The present invention relates to a valve timing control device for an engine that prevents erroneous learning when learning a reference position of a variable valve timing mechanism.

[0002]

2. Description of the Related Art In recent years, an engine with a variable valve timing mechanism provided with a variable valve timing mechanism for adjusting a rotation phase between a crankshaft and a camshaft of the engine has been put to practical use. In an engine with a valve, the valve timing of at least one of the intake valve and the exhaust valve is continuously changed according to the engine operating state.

In this valve timing control, the rotational phase (displacement angle) of the camshaft with respect to the crankshaft, that is, the valve timing, is calculated by processing a signal from a sensor by an electronic control unit. A crank angle sensor that detects a crank angle index such as a protrusion formed at every predetermined crank angle on the crank rotor that rotates in synchronization with the crank rotor and outputs a crank pulse representing the crank angle, and a cam rotor that rotates in synchronization with the cam shaft An actual displacement angle (actual valve timing) of the cam position with respect to the reference crank angle by using a cam position sensor that outputs a cam position pulse representing the cam position by detecting a cam position index such as a projection formed at Variable valve so that the actual valve timing converges to the target valve timing set based on the engine operating state To control the timing mechanism.

In this case, an actual displacement angle (actual valve timing) calculated by an electronic control unit based on a signal from a sensor.
There is a difference (offset) that differs for each individual due to an error in the mounting position of the sensor, aging, and the like between the camshaft and the predetermined displacement angle of the camshaft obtained from the mechanical coupling in the variable valve timing mechanism. It is necessary to learn the reference position of the variable valve timing mechanism and calibrate the apparent actual valve timing calculated based on the signal from the sensor.

The learning of the reference position needs to be in a stable state with a small change in the cam shaft displacement angle in order to prevent erroneous learning. For example, this is disclosed in Japanese Patent Application Laid-Open No. Hei 8-200020. As described above, the process is performed with the most retarded position at which the variable valve timing mechanism is mechanically locked as the reference position (most retarded angle learning). Further, in the prior art disclosed in Japanese Patent Application Laid-Open No. 8-2000020, it is determined whether or not the variable valve timing mechanism has failed, and if it is determined that the variable valve timing mechanism has failed, learning is prohibited and an error is prohibited. Try to prevent learning.

[0006]

However, even in a situation where the system is normal and control is normally performed,
External load applied to the engine, such as when the air conditioner is switched from ON to OFF or from OFF to ON, or when the vehicle is switched from the traveling range to the non-traveling range or from the non-traveling range to the traveling range in a vehicle equipped with an automatic transmission. Fluctuates, the phase between the crankshaft and the cam pulley fluctuates due to bending of the timing belt and the like, and is calculated based on the crank angle detected by the crank angle sensor and the cam position detected by the cam position sensor. The actual displacement angle (actual valve timing) fluctuates.

For this reason, if the reference position is learned using the actual valve timing calculated based on the crank angle detected by the crank angle sensor and the cam position detected by the cam position sensor, the reference value is calculated based on the sensor value. Due to the fluctuation of the calculated actual valve timing, the learning is performed without accurately grasping the deviation from the reference position, and the actual valve timing based on the sensor value is calibrated by the learned value including the error, thereby controlling the valve timing. Disadvantageously deteriorates the controllability of the device.

The present invention has been made in view of the above circumstances, and provides an engine valve timing control device capable of preventing erroneous learning due to a change in an external load on an engine when learning a reference position of a variable valve timing mechanism. It is intended to provide.

[0009]

According to a first aspect of the present invention, there is provided a variable valve timing mechanism for adjusting a rotation phase between a crankshaft and a camshaft of an engine. Learning the deviation between the reference position of the timing mechanism and the actual valve timing calculated from the crank angle and the cam position, calibrating the actual valve timing,
An engine valve timing control device for controlling the variable valve timing mechanism so that the calibrated actual valve timing converges to a target valve timing set based on an engine operating state, the reference position of the variable valve timing mechanism and the actual valve timing And learning stop means for stopping the learning when the external load on the engine changes during learning of the deviation.

A second aspect of the present invention is characterized in that, in the first aspect of the present invention, the learning is stopped only for a set time after the external load changes.

According to a third aspect of the present invention, in the first or the second aspect of the invention, at least one of turning on / off the air conditioner and switching between the running range and the non-running range of the automatic transmission is regarded as a change in the external load. , The learning is stopped.

That is, according to the first aspect of the present invention, the reference position of the variable valve timing mechanism for adjusting the rotational phase between the crankshaft and the camshaft of the engine, and the actual valve timing calculated from the crank angle and the cam position. If the external load on the engine changes while learning the deviation, learning is stopped.

In this case, according to the second aspect of the present invention, the learning suspension period is set to a set time after the external load changes,
In the invention according to claim 3, the air conditioner is turned on / off,
Further, learning is stopped by at least one of switching between the traveling range and the non-traveling range of the automatic transmission as a change in the external load.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 13 relate to an embodiment of the present invention. FIG. 1 is a flowchart of a most retarded angle learning stop determination routine, FIG. 2 is a flowchart of a most retarded angle learning / valve timing control routine, and FIG. FIG. 4 is an explanatory diagram showing a control region, and FIG. 4 is an explanatory diagram showing a change in valve timing of an intake valve with respect to an exhaust valve.
FIG. 6 is a time chart showing a relationship among a crank pulse, a cylinder discrimination pulse, and a cam position pulse, FIG. 6 is an overall configuration diagram of an engine with a variable valve timing mechanism, FIG. 7 is a schematic configuration diagram of a variable valve timing mechanism, and FIG. FIG. 9 is an explanatory view showing the most advanced state of the timing mechanism in the AA section of FIG. 7, FIG. 9 is an explanatory view showing the most retarded state of the variable valve timing mechanism in the AA section of FIG. 7, and FIG. FIG. 11 is a rear view of an intake cam pulley, FIG. 12 is a front view of a cam rotor and a cam position sensor, and FIG. 13 is a circuit configuration diagram of an electronic control system.

First, the overall structure of an engine with a variable valve timing mechanism to which the present invention is applied will be described with reference to FIG. In the figure, reference numeral 1 denotes an engine with a variable valve timing mechanism (hereinafter simply abbreviated as "engine").
1 shows a cylinder gasoline engine. The left and right banks of a cylinder block 1a of the engine 1 include a cylinder head 2
Are provided, and an intake port 2a and an exhaust port 2b are formed in each cylinder head 2 for each cylinder.

As an intake system of the engine 1, an intake manifold 3 communicates with each intake port 2a, and a throttle valve interlocked with an accelerator pedal through an air chamber 4 in which intake passages of respective cylinders are connected to the intake manifold 3. The throttle chamber 5 in which 5a is interposed communicates. An air cleaner 7 is mounted upstream of the throttle chamber 5 via an intake pipe 6, and the chamber 8 communicates with an air intake passage connected to the air cleaner 7.

A bypass passage 9 for bypassing the throttle valve 5a is connected to the intake pipe 6, and the amount of bypass air flowing through the bypass passage 9 is adjusted in the bypass passage 9 according to the valve opening during idling. Thus, an idle control valve 10 for controlling the idle speed is provided.

Further, an injector 11 is disposed immediately upstream of the intake port 2a of each cylinder of the intake manifold 3. In addition, an ignition plug 12 that exposes a discharge electrode at the tip to the combustion chamber is provided in the cylinder head 2 for each cylinder. Each ignition plug 12 is connected to an ignition coil 13 with a built-in igniter.

On the other hand, as an exhaust system of the engine 1, an exhaust pipe 15 is communicated with a collection portion of an exhaust manifold 14 which communicates with each exhaust port 2b of the cylinder head 2, and a catalytic converter 16 is interposed in the exhaust pipe 15. To the muffler 17.

Here, the variable valve timing mechanism of the engine 1 will be described with reference to FIGS.

The rotation of the crankshaft 18 of the engine 1 is controlled by a crank pulley fixed to the crankshaft 18 on each intake camshaft 19 and each exhaust camshaft 20 disposed in each cylinder head 2 of the left and right banks. 21, a timing belt 22, an intake cam pulley 2 interposed on the intake cam shaft 19
3, transmitted through an exhaust cam pulley 24 fixed to the exhaust camshaft 20 and the like, the crankshaft 18 and the camshafts 19, 20
Are set to have a two-to-one rotation angle. The cams 19a provided on the intake camshaft 19 and the exhaust cams (not shown) provided on the exhaust camshaft 20 are each maintained at a rotation angle of 2: 1 with respect to the crankshaft 18. , 20 based on the rotation of the intake valve 25,
The exhaust valve 26 is driven to open and close.

As shown in FIG. 7, between the intake cam shafts 19 of the left and right banks and the intake cam pulleys 23, the intake cam pulleys 23 and the intake cam shafts 19 are relatively rotated to move the intake cam shafts relative to the crankshaft 18. A variable valve timing mechanism 27 of a hydraulic drive type that continuously changes the rotation phase (displacement angle) of the motor 19 is provided. As is well known, the variable valve timing mechanism 27 includes an oil flow control valve 36 including a linear solenoid valve or a duty solenoid valve.
The hydraulic pressure is switched by R (36L),
It is activated by a drive signal from an electronic control unit 60 for engine control, which will be described later. In the following, suffixes L and LH in the reference numerals indicate right banks, and R and RH indicate left banks.

The intake camshaft 19 is rotatably supported between the cylinder head 2 and a bearing cap (not shown), and has three vanes at the tip of the intake camshaft 19 as shown in FIGS. Vane rotor 2 having 28a
8 is attached by a bolt 29 so as to be integrally rotatable.

A housing 30 and a housing cover 31 are attached to the intake cam pulley 23 by bolts 32 so as to be integrally rotatable. A large number of external teeth 23 a for mounting the timing belt 22 are formed on the outer periphery of the intake cam pulley 23.

The intake camshaft 19 is rotatably penetrated through the housing cover 31, and each vane 28a of the vane rotor 28 fixed to the intake camshaft 19 is formed in a housing 30 integral with the intake cam pulley 23. The two fan-shaped spaces 33 are rotatably stored. Each fan-shaped space 33
Are divided into an advance chamber 33a and a retard chamber 33b by the vanes 28a, respectively.

The advance chambers 33a are provided with vane rotors 2 respectively.
8, the intake camshaft 19, and the A port 36a of the oil flow control valve 36R (36L) are communicated through the advance side oil passages 28b, 19b, 34 formed in the cylinder head 2, and the retard chamber 33b is , Each vane rotor 2
8, the intake camshaft 19, and the B port 36b of the oil flow control valve 36R (36L) are communicated via the retard side oil passages 28c, 19c, 35 formed in the cylinder head 2.

The oil flow control valve 36R (36L)
An oil supply port 36c connected to an oil supply passage 40 to which oil, that is, a predetermined oil pressure is supplied from an oil pan 37 via an oil pump 38 and an oil filter 39
And a drain port 36d and 36f communicating with the two drain passages 41 and 42, respectively, and a spool 36g having four lands and three passages formed between the lands is reciprocated in the axial direction. , A port 36a, B port 36b and oil supply port 36
c, and selectively communicates with the drain port 36d or 36f.

In this embodiment, the oil flow control valve 3
Reference numeral 6R (36L) is a four-way control valve having, as an actuator, a linear solenoid which is controlled by an electronic control unit 60 for controlling the engine, and the spool 36g moves in the axial direction in proportion to the current supplied to the linear solenoid. Then, the flow direction of the oil is switched and the opening degree of the passage is adjusted, so that the magnitude of the hydraulic pressure supplied to each of the advance chamber 33a and the retard chamber 33b is adjusted.

Reference numeral 28d denotes a stopper pin inserted through the vane 28a of the vane rotor 28. When the variable valve timing mechanism 27 is in the most retarded state (see FIG. 9), the stopper pin is inserted into a hole 30a formed in the housing 30. Engage and position. The most retarded position of the variable valve timing mechanism 27 due to the mechanical engagement is determined by a rotation phase of the intake camshaft 19 with respect to the crankshaft 18 calculated based on a signal from a sensor in the electronic control unit 60 for engine control. The reference position is used to calibrate the (displacement angle), and the deviation from the actual displacement angle (actual valve timing) of the intake camshaft 19 calculated from the sensor value at this reference position is learned (most retarded angle learning). 8 shows the most advanced state of the variable valve timing mechanism 27, and FIG. 9 shows the most retarded state of the variable valve timing mechanism 27.

The variable valve timing mechanism 27 has a protrusion 43a, 43b, 43c (for each predetermined crank angle) on the outer periphery of a crank rotor 43 which is attached to the crankshaft 18 and rotates synchronously as a sensor for detecting its operating position. 10) and a crank angle sensor 44 for outputting a crank pulse representing the crank angle, and a plurality of projections 45a at equal angles around the outer periphery of a cam rotor 45 fixed to the rear end of the intake cam shaft 19 and rotating synchronously. (See FIG. 12), and a cam position sensor 46R (46L) that outputs a cam position pulse indicating the cam position is used.

The crank pulse output from the crank angle sensor 44 and the cam position sensor 46R (4
6L) is input to the electronic control unit 60 for engine control, and the electronic control unit 60 uses the electronic control unit 60 to calculate the actual displacement angle of the intake cam position with respect to the reference crank angle based on the crank pulse and the cam position pulse. (Actual valve timing) is calculated, and the variable valve timing mechanism 27 is feedback-controlled so that the actual valve timing converges to the target valve timing set based on the engine operating state.

In the present embodiment, the variable valve timing mechanism 27 is provided only on the intake camshaft 19 side, and as shown in FIG.
The opening / closing timing of the intake valve 25 is changed according to the engine operating state. In the linear solenoid type oil flow control valve 36R (36L) employed in the present embodiment, the spool 36g moves to the left as shown in FIG. 8 as the control current value output from the electronic control unit 60 increases. 9, the displacement angle of the intake camshaft 19 with respect to the crankshaft 18 is advanced by moving the spool 36g rightward as shown in FIG. Retard.

That is, a crank pulse output from the crank angle sensor 44 and a cam position output from the cam position sensor 46R (46L) with respect to a target displacement angle (target valve timing) set based on the engine operating state. When the rotational phase of the intake cam position with respect to the reference crank angle, that is, the displacement angle of the intake cam shaft 19 with respect to the crankshaft 18 is advanced based on the pulse, the electronic control unit 60 for engine control is controlled by the oil flow control valve. 36R (36L), the control current value is reduced, and the operation of the variable valve timing mechanism 27 causes the crankshaft 18
When the displacement angle of the intake camshaft 19 with respect to the crankshaft 18 is retarded, the control current value output to the oil flow control valve 36R (36L) is increased. Variable valve timing mechanism 2
7, the intake camshaft 19 with respect to the crankshaft 18
Is advanced.

When the control current value of the oil flow control valve 36R (36L) increases, the spool 36g moves to the left as shown in FIG. 8, and the A port 36a communicates with the oil supply port 36c to change the variable valve timing. The advance chamber 33a of the mechanism 27 is connected to the advance-side oil passages 28b, 19b, 3
4. It communicates with the oil supply passage 40 via the oil flow control valve 36R (36L). In addition, the B port 36b and the drain port 36f communicate with each other,
The retard chamber 33b of the variable valve timing mechanism 27 communicates with the drain passage 42 via the retard oil passages 28c, 19c, 35 and the oil flow control valve 36R (36L).

As a result, the variable valve timing mechanism 27
When oil is supplied to the advance chamber 33a and the hydraulic pressure acting on the advance chamber 33a increases, the oil pressure acting on the retard chamber 33b decreases due to the drain of the oil in the retard chamber 33b, as shown in FIG. As described above, the vane rotor 28 rotates clockwise in the drawing, and the rotational phase of the intake camshaft 19 with respect to the intake cam pulley 23, that is, the displacement angle of the intake camshaft 19 with respect to the crankshaft 18, is advanced, and the intake camshaft is rotated. 19
The opening / closing timing of the intake valve 25 driven by the intake cam 19a is advanced.

Conversely, the oil flow control valve 36R (36
When the control current value of L) decreases, the spool 36g moves to FIG.
As shown in FIG. 8, the A port 36a and the drain port 36d communicate with each other, and the advance chamber 33a of the variable valve timing mechanism 27 is moved to the advance oil passages 28b and 19.
b, 34 and communicate with the drain passage 41 via the oil flow control valve 36R (36L). Also, with this, B
The communication between the port 36b and the oil supply port 36c allows the retard chamber 33b of the variable valve timing mechanism 27 to communicate with the oil supply passage via the retard oil passages 28c, 19c, 35 and the oil flow control valve 36R (36L). Communicate with 40.

Thus, the variable valve timing mechanism 2
7 is advanced by the drain of oil in the advance chamber 33a.
As the oil pressure acting on the retardation chamber 33b decreases, the oil pressure supplied to the retardation chamber 33b increases, and as shown in FIG. 9, the vane rotor 28 rotates counterclockwise in the figure. And the rotational phase of the intake camshaft 19 with respect to the intake cam pulley 23, that is, the displacement angle of the intake camshaft 19 with respect to the crankshaft 18, is retarded.
9 that is driven by the intake cam 19a
Opening / closing timing is retarded.

Next, sensors for detecting the operating state of the engine will be described. Air cleaner 7 for intake pipe 6
Immediately downstream of this, a thermal intake air amount sensor 47 using a hot wire or a hot film is interposed, and a throttle opening sensor 48 is connected to a throttle valve 5 a provided in the throttle chamber 5. I have.

The cylinder block 1a of the engine 1
Knock sensor 49 is attached to the cylinder block 1
A cooling water temperature sensor 51 faces a cooling water passage 50 that connects the left and right banks of FIG. An O2 sensor 52 is provided upstream of the catalytic converter 16.

A crank angle sensor 44 is mounted on the outer periphery of a crank rotor 43 which is mounted on the crankshaft 18 of the engine 1.
Further, a cylinder discriminating sensor 53 is provided opposite to the back surface of the intake cam pulley 23 which makes a half rotation with respect to the crankshaft 18 (see FIG. 7), and a cam rotor fixed to the rear end of the intake camshaft 19 is provided. A cam position sensor 46R (46
L) are provided opposite to each other.

As shown in FIG. 10, the crank rotor 43 has projections 43a, 43b, 43c formed on its outer periphery, and these projections 43a, 43b, 43c are connected to the respective cylinders (# 1, # 2 and # 2). 3, # 4 cylinder) before compression top dead center (BTDC) θ1, θ2, θ3. In the present embodiment, θ1 = 97 ° CA, θ2 = 65
° CA, θ3 = 10 ° CA.

As shown in FIG. 11, on the outer peripheral side of the back surface of the intake cam pulley 23, protrusions 23b, 2
3c and 23d are formed, the protrusion 23b is formed at a position θ4 after the compression top dead center (ATDC) of the # 3 and # 4 cylinders, and the protrusion 23c is composed of three protrusions, and the first protrusion is the # 1 cylinder. ATDC θ5. Further, the projection 23d is formed of two projections, and the first projection is formed at the position of ATDC θ6 of the # 2 cylinder. In the present embodiment, θ4 = 20 ° CA, θ5 = 5 ° CA, θ6 =
20 ° CA. In addition, these cylinder discrimination projections 23
b, 23c, 23d and the cylinder discrimination sensor 53 are provided only in one bank.

Further, the engine 1 employed in this embodiment is 4
Corresponding to the cylinder engine, the cam rotor 45
As shown in FIG. 12, four protrusions 45a for detecting the cam position are formed on the outer periphery, one for each equal angle of 180 ° CA. Each of these projections 45a is operated by the operation of the variable valve timing mechanism 27 so that, based on the compression top dead center of each cylinder, θ7 = BTDC40 ° CA to ATD
It varies between C10 ° CA.

FIG. 12 shows the cam rotor 45 fixed to the intake camshaft 19 on the RH side.
Similarly, a cam rotor 45 is fixedly mounted on the intake camshaft 19 on the side, and a projection 45a for detecting a cam position is provided on the outer periphery of the cam rotor 45.
Four projections 45a are formed at equal angles of ° CA, and these projections 45a are operated by the operation of the variable valve timing mechanism 27 with respect to the compression top dead center of each cylinder as θ8 = BTDC.
It varies between 40 ° CA and 10 ° CA ATDC.

As shown in the time chart of FIG. 5, the crank rotor 43 and the cam rotor 45 are rotated by the rotation of the crankshaft 18, the intake cam pulley 23, and the intake camshaft 19 during the operation of the engine. The projections 43a, 43b, 43c are detected by the crank angle sensor 44, and the crank angle sensor 44 detects θ1, θ2, θ3 (BTDC 97 °, 65 °, 10 °).
CA) of each crank pulse is a half rotation of the engine (18
0 ° CA). Further, between the θ3 crank pulse and the θ1 crank pulse, each protrusion 23b, 23c, 23d of the intake cam pulley 23 is detected by the cylinder discrimination sensor 53, and a predetermined number of cylinder discrimination pulses are output from the cylinder discrimination sensor 53.

Each of the protrusions 45a of the cam rotor 45 fixed to the rear end of each of the intake camshafts 19 of the right bank and the left bank whose rotational phase changes with respect to the crankshaft 18 by the variable valve timing mechanism 27 is a cam position sensor. 46R,
46L, the cam position sensors 46R, 46
L outputs cam position pulses of θ7 and θ8, respectively.

In the following electronic control unit for engine control (hereinafter abbreviated as “ECU”) 60, the engine speed NE is calculated based on the input interval time of the crank pulse output from the crank angle sensor 44. Further, the pattern of the combustion stroke of each cylinder (for example, # 1 cylinder → # 3 cylinder → # 2 cylinder → # 4 cylinder) and the value obtained by counting the cylinder discrimination pulse from the cylinder discrimination sensor 53 by the counter are used. Based on the determination, the cylinders of the combustion stroke cylinder, the fuel injection target cylinder, and the ignition target cylinder are determined. Further, the ECU 60
Based on the crank pulse output from the crank angle sensor 44 (for example, a θ2 crank pulse corresponding to the projection 43b) and the θ7, θ8 cam position pulses output from the cam position sensors 46R, 46L, intake air for the reference crank angle is obtained. The actual displacement angle of the cam position (actual valve timing) is calculated.

The ECU 60 controls the injector 11,
Calculation of control amounts for actuators such as oil flow control valves 36R and 36L for adjusting hydraulic pressure supplied to the spark plug 12, the idle control valve 10, and the variable valve timing mechanism 27, and output of control signals, that is, fuel injection control , Ignition timing control, idle speed control, valve timing control for the intake valve 25, etc., as shown in FIG.
The AM 63, the backup RAM 64, the counter / timer group 65, the I / O interface 66A, and the serial / serial interface (SCI) 66B are mainly configured by a microcomputer connected via a bus line, and supply stabilized power to each unit. Constant voltage circuit 6
7, peripheral circuits such as a drive circuit 68 and an A / D converter 69 connected to the I / O interface 66A are built in.

The counter / timer group 65 is used to generate various counters such as a free-run counter, a counter for counting the input of a cylinder discrimination sensor signal (cylinder discrimination pulse), a fuel injection timer, an ignition timer, and a periodic interrupt. Timers for periodic interrupts, timers for measuring the input intervals of crank angle sensor signals (crank pulses), and watchdog timers for monitoring system abnormalities are collectively referred to for convenience.
A timer is used.

The constant voltage circuit 67 is connected to the battery 71 via a first relay contact of a power supply relay 70 having two relay contacts, and the power supply relay 70 has one end of its relay coil grounded, Is connected to the drive circuit 68 at the other end. A power supply line for supplying power from the battery 71 to each actuator is connected to the second relay contact of the power supply relay 70. One end of an ignition switch 72 is connected to the battery 71, and the other end of the ignition switch 72 is connected to an input port of the I / O interface 66A.

Further, the constant voltage circuit 67 is directly connected to the battery 71, and the ignition switch 72
Is detected and the contact of the power supply relay 70 is closed, power is supplied to each unit in the ECU 60, and regardless of whether the ignition switch 72 is ON or OFF,
A backup power supply is supplied to the backup RAM 64.

Knock sensor 49, crank angle sensor 44, cylinder discriminating sensor 53, cam position sensors 46R and 46L, vehicle speed sensor 54 for detecting vehicle speed, and air conditioner switch 55 are connected to input ports of I / O interface 66A. Further, through an A / D converter 69, the intake air amount sensor 47, the throttle opening sensor 4
8. The cooling water temperature sensor 51 and the O2 sensor 52 are connected, and the battery voltage VB is input and monitored.

The output port of the I / O interface 66A has an idle control valve 10, an injector 1
1. The oil flow control valves 36R, 36L, and the relay coil of the power supply relay 70 are connected via the drive circuit 68, and the ignition coil 13
Igniter 13a is connected.

On the other hand, reference numeral 80 denotes an electronic control unit (TCU) for controlling the transmission, and the ECU 60 for controlling the engine.
Like the above, it is configured around a microcomputer,
The ECUs 60 are connected to an engine control ECU 60 via an SCI 66B so that data can be exchanged with each other.

In the present embodiment, as a speed change drive system connected to the output shaft of the engine 1, a torque converter 86 having a lock-up clutch 85 for engaging an impeller and a turbine is provided. An automatic transmission 90 provided with a clutch mechanism unit including various hydraulic clutches and various hydraulic brakes for performing shift switching and a main transmission mechanism unit including a planetary gear and the like are connected in series. The automatic transmission 90 is provided with a hydraulic control unit 95 integrally formed with various control valves for controlling line pressure and pilot pressure to each mechanism unit.

The TCU 80 receives signals from the throttle opening sensor 48, the coolant temperature sensor 51, and the vehicle speed sensor 54, which are shared with the ECU 60, as well as a turbine speed signal, an ATF oil temperature signal, a brake signal, and a select signal. A signal or the like indicating the operation position (shift range position) of the mechanism section 96 is input, and the engagement, slip, and release of the lock-up clutch 85 are controlled via the hydraulic control section 95, and the shift control of the automatic transmission 90 is controlled. Do.

In the ECU 60 for controlling the engine, the ROM
I / O according to the control program stored in
The detection signal from the sensors / switches input through the interface 66A, the battery voltage, etc.
In addition to processing at 61, transmission control data, operating position (range position) data, control data for the lock-up clutch 85, and the like are received from the transmission control TCU 80 via the SCI 66 B, and these received data are stored in the RAM 63. Based on various data, various learning value data stored in the backup RAM 64, and fixed data stored in the ROM 62, the fuel injection amount, the ignition timing, the duty ratio of the control signal for the idle control valve 10, the oil flow control valve Calculate control current values and the like for 36R and 36L, and perform engine control such as fuel injection control, ignition timing control, idle speed control, and valve timing control.

Here, as described above, in the valve timing control by the variable valve timing mechanism 27,
The rotation phase of the intake cam position with respect to the reference crank angle based on the crank pulse output from the crank angle sensor 44 and the cam position pulse output from the cam position sensor 46R (46L), that is, the intake cam shaft 19 with respect to the crank shaft 18 The actual displacement angle (actual valve timing) is calculated, and the control current value for the oil flow control valves 36R and 36L is calculated so that the actual valve timing converges to the target valve timing set based on the engine operating state. The control current based on the current value is output to the oil flow control valves 36R and 36L to feedback-control the variable valve timing mechanism 27.

At this time, the displacement angle of the intake camshaft 19 based on signals from the crank angle sensor 44 and the cam position sensor 46R (46L) and the displacement of the intake camshaft 19 obtained by mechanical coupling of the variable valve timing mechanism 27. The displacement angle of the intake camshaft 19, which is calculated based on signals from the crank angle sensor 44 and the cam position sensor 46R (46L), in order to compensate for the deviation between the displacement angle and the existing displacement angle,
The variable valve timing mechanism 27 is calibrated by a learning value obtained by the most retarded angle learning based on the most retarded position (see FIG. 9) in a stable state mechanically locked.

During the learning of the most retarded angle, external control such as switching the air conditioner from ON to OFF or from OFF to ON, or switching from the traveling range to the non-traveling range or from the non-traveling range to the traveling range in the shifting operation of the automatic transmission, etc. When a change in the load is monitored and a change in the external load is detected, learning is forcibly performed to prevent erroneous learning due to a change in the phase between the crankshaft 18 and the intake cam pulley 23 due to the bending of the timing belt 22 or the like. Cancel.

That is, the ECU 60 includes a function as a learning stop unit according to the present invention in the valve timing control function, and specifically, realizes the function by the routine shown in FIG.

Hereinafter, processing related to valve timing control by the ECU 60 will be described with reference to the flowcharts shown in FIGS.

First, the ignition switch 72 is turned on.
Then, when the power is supplied to the ECU 60, the system is initialized and each flag and each counter are initialized except for trouble data and data such as various learning values stored in the backup RAM 64.

Next, the starter switch (not shown)
N and the engine starts, every predetermined time (for example,
Every 1 min), the most retarded angle learning stop determination routine of FIG. 1 is executed, the change in the external load applied to the engine is checked, and it is determined whether the learning is permitted or the stop is instructed. Then, in the most retarded angle learning / valve timing control routine of FIG. 2, which is executed at every predetermined period (every predetermined time), the learning condition of the variable valve timing mechanism 27 is learned at the most retarded position (reference position). Not established, or
If the instruction to stop learning is given by a change in the external load, learning of the most retarded position is prohibited. When the learning condition is satisfied and the learning is permitted, the learning of the most retarded position is performed, and the actual valve timing calculated based on the sensor value is determined by the learned value obtained by the most retarded learning. Calibration is performed, and feedback control to target valve timing suitable for the engine operating state is performed using the calibrated actual valve timing.

First, the routine for determining the most retarded angle learning stop in FIG. 1 will be described. In this routine, in the first step S101, it is determined whether or not the input signal from the air conditioner switch 55 has been inverted, that is, from the air conditioner ON to the air conditioner O
It is switched to the FF or from the air conditioner OFF to the air conditioner ON, and it is checked whether or not the external load applied to the engine 1 has changed.

When the input signal of the air conditioner switch 55 is inverted and there is a change in the external load, the process proceeds from step S101 to step S102, where the most retarded angle learning stop flag FLRCCL is set (FLRCCL ← 1).
In step S108, the count value CLRC for measuring the time after the external load change, that is, the elapsed time after the learning is stopped.
CL is cleared (CLRCCL ← 0) and the routine exits. The most retarded angle learning suspension flag FLRCCL is referred to in the most retarded angle learning / valve timing control routine of FIG. 2 and instructs to suspend the most retarded angle learning when FLRCCL = 1.
When LRCCL = 0, the most retarded angle learning is permitted.

If the input signal of the air conditioner switch 55 is not inverted at step S101,
Proceeding from step S101 to step S103, the TCU
Referring to the transmission operation position (range position) data received from 80, a change in the external load due to the switching of the non-travel range ← → travel range is examined.

As a result, if there is a switch from the non-traveling range to the traveling range or from the traveling range to the non-traveling range, similarly, in order to instruct the stop of the learning, the maximum retard angle learning is stopped in step S102. Flag FLRCCL
And exits the routine via step S108.
If the running range has not been switched, the process proceeds to step S104, and the value of the most retarded angle learning suspension flag FLRCCL is referred to.

Here, the change in the external load due to the switching of the traveling range is, in a vehicle equipped with a manual transmission,
Since it can be ignored in practice, the above-described step S1
03 is unnecessary. That is, ON / OFF of the air conditioner
The maximum delay learning is stopped only when necessary when there is a relatively large change in external load, such as when switching between the automatic transmission and the driving range of the automatic transmission ← → non-driving range, minimizing the decrease in learning frequency. Suppress and secure controllability.

Then, in step S104, FL
If the stop of learning is not instructed at RCCL = 0,
When the learning is stopped by FLRCCL = 1, the process proceeds to step S105, where the count value CLRCCL is compared with the set value CLRCS (for example, a value corresponding to several seconds), and the elapsed time after the learning is stopped. It is checked whether a set time determined by the set value CLRCS has elapsed.

As a result, in step S105, C
If LRCCL <CLRCS and the elapsed time after the stop of learning has not reached the set time, the count value CLRCCL is counted up in step S106 (CLRCCL ←
CLRCCL + 1) Exit the routine, and CLRCCL ≧ C
When the elapsed time after the stop of the learning reaches the set time in the LRCS, it is determined that the change in the load causing the stop of the learning has stopped and the state has become stable, and the maximum retardation learning stop flag FLRCCL is cleared in step S107. (FLRCCL
← 0) The most retarded angle learning is permitted, the count value CLRCCL is cleared in step S108, and the routine exits.

That is, during the most retarded angle learning, the O
If there is a change in the external load due to switching from N to OFF or from OFF to ON or switching from the driving range to the non-traveling range or from the non-traveling range to the driving range in the gear shifting operation, the learning is temporarily stopped. The deviation from the most retarded position cannot be accurately grasped due to the fluctuation of the actual displacement angle based on the crank angle detected by the crank angle sensor 44 and the cam position detected by the cam position sensor 46R (46L). Learning is prevented from being performed, and deterioration in controllability of valve timing control due to erroneous learning is avoided. In addition, by stopping the learning for a set time after the load change, a decrease in the learning frequency can be minimized, and the learning can be permitted while the engine is in a stable state, thereby improving the learning accuracy.

In contrast to the above-described routine for determining the suspension of the most retarded angle learning, the routine for the most retarded angle learning and valve timing control shown in FIG. 2 determines in step S201 the crank pulse output from the crank angle sensor 44 and the cam position sensor 46R.
(46L) and the cam position pulse output from
An actual valve timing (actual displacement angle) VTB of the intake camshaft 19 with respect to the crankshaft 18 is calculated. Here, the actual valve timing VTB is an apparent actual valve timing calculated from the sensor value, and is a learning value obtained by using the most retarded position of the variable valve timing mechanism 27 as a reference position in step S213 described later. The deviation of the sensor value with respect to the reference position is calibrated by the (most retarded learning value VTRLR).

The calculation of the actual valve timing VTB based on the output signals from the crank angle sensor 44 and the cam position sensor 46R (46L) is performed by specifically calculating the rotation time per unit angle from the engine speed NE calculated by the crank pulse. , And in this time per unit angle rotation,
By multiplying the time from when the θ2 crank pulse is input to when the θ7 and θ8 cam position pulses are input, the rotational phase of the intake cam position with respect to the reference crank angle by the θ2 crank pulse, that is, the intake camshaft 19 with respect to the crankshaft 18 Is performed by converting into the displacement angle VTB.

Next, the routine proceeds to step S202, where the basic fuel injection pulse width Tp (= K × Q / N) representing the engine load
E; Q is intake air amount, K is injector characteristic correction constant)
Search the table based on the engine speed NE and
Target valve timing (target displacement angle) V by interpolation calculation
Set TTGT.

That is, as shown in FIG. 3, the valve timing control region is divided into four regions in accordance with the operation state according to the engine load and the engine speed, and the target valve timing VTTGT is set to optimize the engine 1. The target valve timing VTTG is controlled in a low load, low speed idle region.
T is set to 0 °, the opening / closing timing of the intake valve 25 is controlled to the most retarded state where the advance amount is 0 °, and the overlap between the exhaust valve 26 and the intake valve 25 is eliminated to stabilize idle rotation.

In the medium load operation range, the target valve timing VTTTGT is set to a small to medium advance angle, the opening / closing timing of the intake valve 25 is controlled to the advanced side, and the exhaust valve 26 and the intake valve 25 By increasing the amount of overlap and increasing the internal EGR rate, the pumping loss of the engine is reduced and fuel efficiency is improved. On the other hand, in the high load operation region, the target valve timing VTTGT is set to a large advance amount. The opening / closing timing of the intake valve 25 is controlled to be more advanced than the medium load range, and the exhaust valve 26 and the intake valve 25 are controlled.
To increase the filling efficiency and scavenging efficiency, thereby improving the engine output. Further, in the low-load, high-speed operation region, the target valve timing VTTGT is advanced by a small amount to control the opening / closing timing of the intake valve 25 to the retard side, thereby reducing the valve overlap amount to prevent the engine from over-rotating. .

In the front intake valve 25 and the exhaust valve 26 of each cylinder, the valve overlap amount of the intake valve 25 at the most retarded angle with respect to the exhaust valve 26 is, for example, 6 ° CA, and the valve overlap amount at the time of the most advanced angle is, for example, 5
It is set to 6 ° CA. In addition, the intake valve 2 of each cylinder
5. Among the exhaust valves 26, in the rear intake valve 25 and the exhaust valve 26, the valve overlap amount of the intake valve 25 at the most retarded angle with respect to the exhaust valve 26 is set to, for example, 10 ° CA, and the most advanced angle is set. The valve overlap amount at that time is set to, for example, 60 ° CA. In this case, the rotation phase of each intake camshaft 19 with respect to the crankshaft 18 (the intake cam pulley 23) is changed by a maximum of 50 ° CA by the variable valve timing mechanism 27.

In the following step S203, it is checked whether or not the set target valve timing VTTTGT is at the most retarded position of 0 ° CA. If the target valve timing VTTGT is not at the most retarded position of 0 ° CA, the process jumps from step S203 to step S212 without performing the most retarded angle learning, and the target valve timing VTTG is reached.
The count value C for measuring the duration of the feedback control with T set to 0 ° CA is cleared (C ← 0), and the target valve timing VT is determined in step S213 and subsequent steps.
A feedback control process to the TGT is performed.

In the feedback control processing to the target valve timing VTTTGT, first, in step S213,
The most retarded learning value VTRELR from the backup RAM 64
Is read out and added to the actual valve timing VTB to calculate the actual valve timing VT in which the deviation of the most retarded position is calibrated (VT ← VTB + VTRELR).

Next, the routine proceeds to step S214, where the holding current value IVTH of the oil flow control valve 36R (36L) is set to
A feedback current value (K × (VTTGT−VT)) obtained by multiplying the deviation between the target valve timing VTGTGT and the actual valve timing VT after calibration by the proportional gain K is added, and the control current value of the oil flow control valve 36R (36L) is added. Calculate IVT. Then, in step S215, the control current value IVT is set so as to output the control current based on the control current value IVT to the oil flow control valve 36R (36L) via the drive circuit 68, and the routine exits.

The holding current value IVTH is determined by holding the spool 36g of the oil flow control valve 36R (36L) at a position where the A port 36a and the B port 36b are closed with its land, and the advance angle on the cylinder head 2 side. Side oil passage 3
4. The oil flow control valve 36
By shutting off the oil supply port 36c and the drain ports 36d and 36f of L (36R), the vane rotor 28 of the variable valve timing mechanism 27 is not displaced to the advance side or the retard side, and the predetermined target valve timing is achieved. This is a current value for maintaining the converged steady state, and is learned for each oil flow control valve 36R (36L) of an individual control system.

The control current value IVT of the oil flow control valve 36R (36L) is a feedback current value (K × (VTTG) corresponding to the deviation between the target valve timing VTTGT and the actual valve timing VT with respect to the holding current value IVTH.
T-VT)) (for example, IVT = 100
mA to 1000 mA), the stroke of the spool 36g is changed, the amount of connection between the advance-side oil passage 34 or the retard-side oil passage 35 and the oil supply passage 40, the advance-side oil passage 34 or the retard-side oil passage 35 And the connection amount between the drain passages 41 and 42 is changed between 0 and 100%,
Actual valve timing VT is equal to target valve timing VTT
Feedback control is performed so as to converge to GT.

That is, the target valve timing VTTG
When the actual valve timing VT is retarded with respect to T, the control current value IVT of the oil flow control valve 36R (36L) is increased, and the spool 36g connects the advance-side oil passage 34 to the oil supply passage 40. It moves in a direction to increase the amount and the connection amount between the retard side oil passage 35 and the drain passage 42. As a result, the hydraulic pressure of the advance chamber 33a of the variable valve timing mechanism 27 increases, and the retard chamber 33
The oil pressure b decreases, the vane rotor 28 rotates clockwise (see FIG. 8), and the rotational phase of the intake camshaft 19 with respect to the intake cam pulley 23, that is, the rotational phase (displacement angle) of the intake camshaft 19 with respect to the crankshaft 18. Is advanced,
The opening / closing timing of the intake valve 25 driven by the intake cam 19a of the intake cam shaft 19 is advanced.

Conversely, the target valve timing VTT
When the actual valve timing VT is advanced with respect to GT, the control current value IVT of the oil flow control valve 36R (36L) is reduced, and the spool 36g connects the retard side oil passage 35 to the oil supply passage 40. It moves in a direction to increase the amount and the amount of connection between the advance side oil passage 34 and the drain passage 41. As a result, the hydraulic pressure of the advance chamber 33a of the advance chamber 33a of the variable valve timing mechanism 27 decreases, and the hydraulic pressure of the retard chamber 33b increases.
Rotates in the counterclockwise direction (see FIG. 9), and the rotation phase (displacement angle) of the intake cam shaft 19 with respect to the intake cam pulley 23, that is, the rotation phase (displacement angle) of the intake cam shaft 19 with respect to the crank shaft 18, is retarded. The opening / closing timing of the intake valve 25 driven by the intake cam 19a of the shaft 19 is retarded.

Then, when the actual valve timing VT converges to the target valve timing VTTGT (VTTTGT =
VT), the feedback current value becomes 0, and the spool 36g of the oil flow control valve 36R (36L) moves to a position where the advance side oil passage 34 and the retard side oil passage 35 are closed, and the variable valve timing mechanism 27 The vane rotor 28 is stopped and held.

On the other hand, if the target valve timing VTTTGT is at the most retarded position of 0 ° CA in step S203, the process proceeds to step S204, where the operating state of the engine 1 is an idle state after the completion of warm-up, and learning is performed. Check whether the condition is satisfied. In the idle state after the completion of engine warm-up, the engine cooling water temperature based on a signal from the cooling water temperature sensor 51 is set to a set temperature (for example, 70 ° C.).
In the case where the above is described and the throttle opening based on the signal from the throttle opening sensor 48 indicates that the throttle valve is fully closed, it is determined that the engine is in the idle state after the completion of engine warm-up.

If the operating state of the engine 1 is not the idle state after the completion of warm-up, the aforementioned step S2
Then, the process jumps to step S213 and executes feedback control for setting the target valve timing VTTGT to the most retarded position in step S213 and thereafter. If the operating state of the engine 1 is the idle state after the completion of the warm-up and the learning condition is satisfied, the process proceeds to step S204 and the most retarded learning stop flag F
Refer to the value of LRCCL.

As a result, if FLRCCL = 1 and the stop of the most retarded angle learning is instructed, the most retarded angle learning is stopped and the process jumps to step S212, where FLRCCL is reached.
= 0, if the most retarded angle learning is permitted, step S2
At 06, the count value C becomes equal to the set value Cs (for example, 1 to 3 seconds).
It is checked whether or not the value is equal to or longer than the value (equivalent to the set time of c).

Then, in step S206, C <
In the case of Cs, after counting up the count value C in step S207 (C ← C + 1), step S213
Then, the feedback control processing for setting the target valve timing to the most retarded position by jumping to is continued, and when C ≧ Cs, the most retarded learning is performed in steps S208 to S211.

That is, the target valve timing VTTG
By determining whether or not the feedback control for setting T to 0 ° CA has continued for a set time, it is determined whether or not the variable valve timing mechanism 27 has completely reached the most retarded state. It avoids the most retarded learning when it is not completely in the most retarded state, thereby preventing erroneous learning.

In the most retarded angle learning after step S208,
First, in step S208, the actual valve timing VTB
(VTB-VTR)
ELR is equal to the set value AGL1 (for example, 0.050 ° C.)
Negative lower limit of the permissible error width determined by A)-
It is checked whether it is AGL1 or less.

As a result, in step S208, V
If TB−VTRLR ≦ −AGL1, the process proceeds to step S209, where the deviation (VTB−VTRELR) is reduced by the weight n and added to the most recent retarded learning value VTRLR up to the previous time, and a new most retarded learning value VTRELR is obtained. To update the learning value of the backup RAM 64 (VTRLR ←
(VTB-VTRELR) / n).

In step S208, VTB
If -VTRELR> -AGL1, step S208
Then, the process proceeds to step S210, and further, a deviation (VTB) between the actual valve timing VTB and the most retarded learning value VTLELR.
−VTRELR) is checked to see if it is equal to or greater than the allowable upper limit AGL1.

Then, in step S210, (VT
B-VTRELR) <AGL1, that is, -A
If GL1 <(VTB−VTRELR) <AGL1 and the deviation between the actual valve timing VTB and the maximum retardation learning value VTRELR falls within an allowable range, the maximum retardation learning value V
The process jumps to step S212 without updating TLERR, and if (VTB-VTRELR) ≧ AGL1, the process proceeds to step S211 to determine the latest retarded learning value VTR up to the previous time.
Set value AGL2 in ELR (for example, 0.025 ° CA)
Is updated as the new maximum retardation learning value VTRLR, and the learning value of the backup RAM 64 is updated (VTR
ELR ← VTRLR + AGL2).

Then, after updating the most retarded angle learning value VTRLR, the count value C is cleared in step S212, and step S21 is performed using the updated most retarded angle learning value VTRELR.
The valve timing control is performed in the same manner after the third step.

That is, since the learning is performed in a stable state where there is no change in the external load to the engine, erroneous learning due to the change in the external load is prevented, the learning accuracy is improved, and the control reliability of the valve timing control can be improved. .

[0098]

As described above, according to the first aspect of the present invention, the reference position of the variable valve timing mechanism for adjusting the rotational phase between the crankshaft and the camshaft of the engine, the crank angle and the cam If the external load on the engine changes while learning the deviation from the actual valve timing calculated from the position, the learning is stopped. Prevent erroneous learning due to phase fluctuation,
Deterioration of controllability of valve timing control due to erroneous learning can be avoided beforehand, and control reliability can be improved.

In this case, according to the second aspect of the present invention, the learning suspension period is set to the set time after the external load is changed. Therefore, in addition to the effect of the first aspect, the learning frequency can be reduced. It is possible to perform learning in a state where the engine is stable while minimizing the decrease, and it is possible to improve learning accuracy.

According to the third aspect of the invention, at least one of the on / off of the air conditioner and the switching between the running range and the non-running range of the automatic transmission is stopped as a change in the external load, and the learning is stopped. With a change in load, learning is stopped only when necessary without interrupting learning,
In addition to the effect of the invention described in claim 1 or the effect of the invention described in claim 2, controllability can be secured by minimizing a decrease in learning frequency.

[Brief description of the drawings]

FIG. 1 is a flowchart of a most retarded angle learning stop determination routine.

FIG. 2 is a flowchart of a most retarded angle learning / valve timing control routine;

FIG. 3 is an explanatory diagram showing a control region of valve timing;

FIG. 4 is an explanatory diagram showing a change in valve timing of an intake valve with respect to an exhaust valve.

FIG. 5 is a time chart showing a relationship among a crank pulse, a cylinder discrimination pulse, and a cam position pulse.

FIG. 6 is an overall configuration diagram of an engine with a variable valve timing mechanism.

FIG. 7 is a schematic configuration diagram of a variable valve timing mechanism.

FIG. 8 shows the most advanced state of the variable valve timing mechanism in FIG. 7;
FIG.

FIG. 9 shows the most retarded state of the variable valve timing mechanism in FIG. 7;
FIG.

FIG. 10 is a front view of a crank rotor and a crank angle sensor.

FIG. 11 is a rear view of the intake cam pulley.

FIG. 12 is a front view of a cam rotor and a cam position sensor.

FIG. 13 is a circuit configuration diagram of an electronic control system.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Engine with a variable valve timing mechanism 18 ... Crankshaft 19 ... Intake camshaft 27 ... Variable valve timing mechanism 60 ... Electronic control device (learning stop means) VTB ... Actual valve timing VTTGT ... Target valve timing CLRCS ... Set value (set time) Equivalent value)

Continued on the front page F term (reference) 3G016 AA08 AA11 AA19 BA03 BA06 BA28 BA38 BA39 BB04 DA06 GA06 3G084 BA23 CA00 DA04 EA11 EB18 EB19 FA07 FA10 FA18 FA20 FA25 FA33 FA38 3G092 AA11 AA15 DA01 DA02 DA09 DG05 EA09 EC22 HA01Z HA06Z HA13X HA13Z HC05Z HD05Z HE01Z HE03Z HE05Z HE08Z HF04Z HF12Z 3G093 AA05 BA14 CA08 CB08 DA01 DA05 DA06 DA07 DA09 DB11 DB25 EA15 EC04 FA09 FA11

Claims (3)

[Claims] A variable valve timing mechanism for adjusting a rotation phase between a crankshaft and a camshaft of an engine;
The actual valve timing is calibrated by learning the deviation between the reference position of the variable valve timing mechanism and the actual valve timing calculated from the crank angle and the cam position, and the calibrated actual valve timing is set based on the engine operating state. An engine valve timing control device that controls the variable valve timing mechanism so as to converge to valve timing, wherein when a deviation between a reference position of the variable valve timing mechanism and the actual valve timing is learned, when an external load on the engine changes. An engine valve timing control device, comprising: a learning stopping means for stopping learning. 2. The engine valve timing control device according to claim 1, wherein the learning is stopped for a set time after the external load changes. 3. The learning according to claim 1, wherein at least one of turning on / off an air conditioner and switching between a running range and a non-running range of the automatic transmission is set as a change in an external load, and the learning is stopped. A valve timing control device for an engine according to the above.